Updated 5:12 p.m. Tennessee Republican Stephen Fincher announced Monday that he would not seek a fourth U.S. House term.

“I am humbled by the opportunity to serve the people of West Tennessee, but I never intended to become a career politician. The last six years have been the opportunity of a lifetime, and I am honored to have been given the chance to serve," Fincher said in a statement.

A fierce proponent of reauthorizing the Export-Import Bank, Fincher, a member of the Financial Services Committee, split with leadership over the issue and last fall led the effort to reauthorize the bank via discharge petition . Earlier in 2015, Republicans in the House had let the export credit agency's authorization expire .

First elected in 2010, Fincher won re-election in 2014 with 70 percent of the vote. Republicans have carried his district at the presidential level by comfortable double-digit margins.

Shelby County is the district's biggest Republican base. "So long as the potential primary doesn’t get diced up, any name that comes out of east Shelby County would have a good jumping off point," one Republican in the state said.

Among those who Republican sources mentioned as potential candidates are:

Another favorite would be state Senate Majority Leader Mark Norris, who sources say has a substantial following and has been behind conservative reforms within the state party. He's also been mentioned as a 2018 gubernatorial candidate.

State Sen. Ed Jackson

Shelby County District Attorney Amy Weirich

Shelby County GOP Chairman Mary Wagner, a lawyer in Memphis.

Republican National Committee General Counsel and committeeman John Ryder.

Scott Golden, Fincher's district director and a member of the Tennessee GOP State Executive Committee.

Radiologist George Flinn, a perennial candidate and self-funder, who placed third in 2014's Senate primary against Sen. Lamar Alexander.

Ron Kirkland, a doctor who lost to Fincher in the 2010 primary. He hails from Jackson, the other major GOP population center in the district, and has been an advocate for Gov. Bill Haslam's Insure TN plan to expand Medicaid.

Matthew Stowe, district attorney general for the 24th judicial district, who clerked for former Supreme Court Justice Sandra Day O'Connor.

State Rep. Bill Sanderson of Dyersburg

State Rep. Steve McManus

Among state legislators who may excite tea party supporters are state Sen. John Stevens and state Rep. Andy Holt.

Shelby County Mayor Mark Luttrell is expected to be able to raise money.

The primary race for the safe Republican seat will likely be crowded and with the filing deadline not until April 7, there's plenty of time for more names to emerge. Many Republicans who had been eyeing this seat, one Republican source said, were banking on Fincher not making moves until 2018 and were caught off guard by his Monday announcement. "The question is, who can ramp up their operation at the drop of a hat?" the source said. So far, Norris and Kelsey are the two most widely-cited front runners.